Just yesterday I had a very realistic dream about drinking. I was surprised when I realized that I was still sober. The dream was so real. It was the first (or second?) dream where I drank in the dream. (My dream happened the night after I had a long conversation with a friend about the last time I drank. It felt like a very integrating conversation. Very positive.)
I have no great insight. I don't think dreaming about using is in any way a sign of being at risk of using. Could be that you are moving to a deeper level of sobriety and your unconscious mind is processing it. Or maybe it is just random stuff.
You could journal with your 'unconscious'. Ask what you need to know about the dream and then just write whatever comes without filtering anything.